TIME-DOMAIN MODELING OF SCREECH-DAMPING LINERS IN COMBUSTORS AND AFTERBURNER

Other conference contribution, 2011

Combustor or afterburner instabilities such as buzz and screech modes can lead to major damage in gas turbines. Acoustic liners may be very effective for damping screech modes, but are also challenging to model in CFD/CAA analysis. A new time-domain porous wall sub-model is presented which enables the inclusion of acoustic liners in unsteady compressible flow solvers. The model includes linear and non-linear loss as well as inertial effects, thereby yielding the correct frequency depen-dent damping. Validation of the model has been carried out for standard Helmholtz type acoustic liners with zero grazing flow. Numerical studies have also been performed for an afterburner test case, with the aim of optimizing a possible screech liner. These studies include unsteady RANS com-putations and Arnoldi eigenmode extraction based on an LNSE solver.